Mobile Internet Protocol (also referred to herein as Mobile IP or MIP) is a solution for seamless mobility on a network such as, for instance, the global Internet or a private network, that is scalable, robust and secure, and that allows mobile entities such as mobile devices or “mobile nodes” that may be, for instance, radios, phones, laptops, PDAs, etc., to maintain ongoing communications while changing their point of attachment to the network. Specifically, each mobile node is always identified by its home address (regardless of its current point of attachment to the network), which provides information about its point of attachment to a home network. However, when the mobile node is connected to the network outside of its home network, for example, when visiting a foreign network or a foreign domain, the mobile node is also associated with a care-of address that provides information about its current point of attachment.
Mobile IP provides for a registration process for registering the care-of address with a network entity called a home agent (“HA”) whose point of attachment, for example, its IP address, is in the mobile node's home network. The home agent is a router on the mobile node's home network that tunnels datagrams (also known in the art as data packets) for delivery to the mobile node when it is away from home, and maintains current location information for the mobile node. Registration is what enables the home agent to send the datagrams destined for the mobile node through a tunnel to the care-of address. After arriving at the end of the tunnel, each datagram is then delivered to the mobile node. Registration may be performed via a network entity called a foreign agent (“FA”) whose point of attachment is in the visited network and whose IP address is the care-of address for the mobile node. The foreign agent is a router on the mobile node's visited network that provides routing services to the mobile node when registered with the foreign agent.
A mobile network is an IP subnet that changes its point of attachment to the infrastructure. One or more mobile routers are usually present in the mobile network to serve as a gateway for the nodes on the mobile network. The mobile router is the entity that changes its IP point of attachment—it hides the mobility from the mobile network. Hence, the nodes on the mobile network are unaware of the changes in points of attachment of the mobile router. Different types of nodes, termed as ‘mobile network nodes (MNNs)’ may be present on the mobile network, including fixed nodes that do not roam out of the mobile network, referred to as ‘local fixed nodes (LFNs)’ and mobile nodes that may roam in and out of the mobile network. Further, two types of mobile nodes may attach to the mobile network—nodes whose “home” is on the mobile network (i.e., the home addresses of these nodes come from the IP subnet space of the mobile network), termed as ‘home mobile nodes (HMNs)’ and nodes that are visiting the mobile network (i.e., nodes whose “home’ is not on the mobile network), termed as ‘visiting mobile nodes (VMNs)’. The term Mobile Node refers to either a HMN or a VMN in generic terms. The term Mobile Entity refers to one of a mobile router or a mobile node.
Accordingly, a mobile entity such as a mobile node or a mobile router should typically be dynamically configured with one or more mobility configuration parameters upon power-up, for example by being assigned or allocated a home agent address, an Internet Protocol (IP) home address, security associations, a Virtual Private Network (VPN) server, etc. Further, there is often a need for such mobility configuration parameter assignments being coordinated among different mobile entities. For example, a HMN may need to be assigned the same home agent address as its home mobile router for optimal operation. As another example, two mobile nodes may need to be assigned the same multicast security association parameters to be able to participate in a multicast session. One way of configuring a mobile entity is through static assignments. However, static assignments are cumbersome and do not allow for load balancing and dynamic failure recovery.
Another way of configuring a mobile device is through dynamic assignments. Typically, dynamic assignments of one or more mobility configuration parameters such as home addresses is desirable because it preserves IP address space since it eliminates the need to have pre-allocated IP addresses for all mobile entities in the system and it removes the complex configurations involved in static assignments. However, the known means for accomplishing dynamic assignments of mobility configuration parameters suffers from some shortcomings.
For example, one method of dynamic assignment of home agents and home IP addresses essentially requires two roundtrip Mobile Internet Protocol (MIP) registrations when a requested home agent is different from an assigned home agent, and thus requires separate mobile node—home agent security associations for both home agent entities. Moreover, if the security associations are configured to be dynamically set up, this may result in increased delays. This method is only applicable to mobile nodes and fails to address dynamic assignments in mobile networks. More particularly, the method does not provide a method of coordinating assignments of such parameters between different groups of mobile entities—such as coordinating assignment of home agent addresses between mobile routers and nodes serviced by the mobile routers.
Another method of dynamic assignments of mobility configuration parameters, Dynamic Host Configuration Protocol (“DHCP”), does not work when the mobile device is powering up away from the home domain. The DHCP server, in this case, will not know the appropriate parameters corresponding to the mobile device's home domain. Thus, this is not a viable alternative for nodes roaming beyond the home domain. Also, this method does not provide a method of coordinating assignments of such parameters between different groups of mobile entities—such as coordinating assignment of home agent addresses between mobile routers and nodes serviced by the mobile routers. Hence, there is a need to address the above issues and provide a method for dynamic allocation of mobility configuration parameters with the ability to group entities and provide mutually consistent parameters.